Make HTMLSlotElement.distributedNodeNextTo&distributedNodePreviousTo faster

third_party/WebKit/Source/core/html/HTMLSlotElement.cpp

Index: third_party/WebKit/Source/core/html/HTMLSlotElement.cpp
diff --git a/third_party/WebKit/Source/core/html/HTMLSlotElement.cpp b/third_party/WebKit/Source/core/html/HTMLSlotElement.cpp
index 230144be09fef59eae872e1986c2f5ecaaa7d010..897a2716098d07b85bdcb4fa7bb73b066b8da202 100644
--- a/third_party/WebKit/Source/core/html/HTMLSlotElement.cpp
+++ b/third_party/WebKit/Source/core/html/HTMLSlotElement.cpp
@@ -83,32 +83,47 @@ void HTMLSlotElement::appendAssignedNode(Node& node)
 
 void HTMLSlotElement::appendDistributedNode(Node& node)
 {
+    size_t size = m_distributedNodes.size();
     m_distributedNodes.append(&node);
+    m_distributedIndices.set(&node, size);
 }
 
 void HTMLSlotElement::appendDistributedNodesFrom(const HTMLSlotElement& other)
 {
+    size_t index = m_distributedNodes.size();
     m_distributedNodes.appendVector(other.m_distributedNodes);
+    for (WillBeHeapHashMap<RawPtrWillBeMember<const Node>, size_t>::const_iterator it = other.m_distributedIndices.begin(); it != other.m_distributedIndices.end(); ++it) {

[kochi, 2016/01/27 08:29:13]

You can write "for (const auto& it = other.m_distributedIndices.begin; ...)".
Or even shorter, you can write "for (const auto& it :
other.m_distributedIndices) ..."
(in this case "it" becomes a reference of iterated object rather than
a pointer to iterated object, the next line will become it.key from
it->key).

[yuzuchan, 2016/02/01 05:40:42]

Done.

+        const Node* node = it.get()->key;

[kochi, 2016/01/27 08:29:13]

You can write "it->key".

[yuzuchan, 2016/02/01 05:40:42]

Done.

+        m_distributedIndices.set(node, index);
+        index++;

[kochi, 2016/01/27 08:29:13]

You can write line97 as m_distributedIndices.set(node, index++);

[yuzuchan, 2016/02/01 05:40:42]

Done.

+    }
 }
 
 void HTMLSlotElement::clearDistribution()
 {
     m_assignedNodes.clear();
     m_distributedNodes.clear();
+    m_distributedIndices.clear();
 }
 
 Node* HTMLSlotElement::distributedNodeNextTo(const Node& node) const
 {
-    size_t index = m_distributedNodes.find(&node);
-    if (index == kNotFound || index + 1 == m_distributedNodes.size())
+    WillBeHeapHashMap<RawPtrWillBeMember<const Node>, size_t>::const_iterator it = m_distributedIndices.find(&node);

[kochi, 2016/01/27 08:29:13]

You can write "const auto it = ...".

[yuzuchan, 2016/02/01 05:40:42]

Done.

+    if (it == m_distributedIndices.end())
+        return nullptr;
+    size_t index = it.get()->value;

[kochi, 2016/01/27 08:29:13]

You can write "it->value".

[yuzuchan, 2016/02/01 05:40:42]

Done.

+    if (index + 1 == m_distributedNodes.size())
         return nullptr;
     return m_distributedNodes[index + 1].get();
 }
 
 Node* HTMLSlotElement::distributedNodePreviousTo(const Node& node) const
 {
-    size_t index = m_distributedNodes.find(&node);
-    if (index == kNotFound || index == 0)
+    WillBeHeapHashMap<RawPtrWillBeMember<const Node>, size_t>::const_iterator it = m_distributedIndices.find(&node);

[kochi, 2016/01/27 08:29:13]

You can write "const auto it = ...".

[yuzuchan, 2016/02/01 05:40:42]

Done.

+    if (it == m_distributedIndices.end())
+        return nullptr;
+    size_t index = it.get()->value;

[kochi, 2016/01/27 08:29:13]

You can write "it->value".

[yuzuchan, 2016/02/01 05:40:42]

Done.

+    if (index == 0)
         return nullptr;
     return m_distributedNodes[index - 1].get();
 }
@@ -202,8 +217,11 @@ void HTMLSlotElement::updateDistributedNodesWithFallback()
 
 DEFINE_TRACE(HTMLSlotElement)
 {
+#if ENABLE(OILPAN)
     visitor->trace(m_assignedNodes);
     visitor->trace(m_distributedNodes);
+    visitor->trace(m_distributedIndices);
+#endif
     HTMLElement::trace(visitor);
 }